1. Technical Field of the Invention
The present invention relates generally to ultra-miniature electrically powered vehicles which, due to the configuration of certain key elements, are constructed smaller and more compactly than other competitive vehicles of this type.
2. Description of the Relevant Art
A toy consisting of a miniature, electrically powered vehicle which is caused to operate on a continuous track enjoys wide popular appeal. The track has at least a pair of electrical rails embedded under its surface which contact a pair of pick-up shoes carried by the vehicle.
FIGS. 2, 4 and 6 represent a typical miniature, electrically powered vehicle of the prior art which is currently in use. Vehicle 20 employing molded plastic body 11 is caused to frictionally fit over and engage chasis 23. In the depicted configuration, electric motor 7, having magnets 32, is directly linked to drive shaft 16. The shaft is terminated by drive pinion 21 which engages crown gear 22 fixed to rear axle 13. Upon energizing motor 7, rear axle 13 is caused to turn which, as a consequence, spins rear wheels 15.
The size of prior miniature, electrically powered vehicle 20 is such that the plane established by drive shaft 16 is substantially coincident with the plane of rear axle 13. As a consequence, drive pinion 21 and crown gear 22 are all that is required to cause rear axle 23 to turn upon the urging of draft shaft 16.
It is intended that vehicles 10, of the present invention, and 20, of the prior art, ride upon tracks 41 and 42, respectively. In doing so, guide pins 25 and 24 extend downward below each chassis and into a slotted track to assist in maintaining the toy vehicles on their respective roadways.
In operation, prior art vehicle 20 employs pick-up shoes 18 extending downward from the bottom of chasis 23 such that each pick-up shoe engages one of the track rails and remains in sliding contact with the rail as the vehicle moves along the track thereby delivering electric power to the vehicle.
As shown in FIG. 6, electric motor 7 mounted in chasis 23 receives electric power through pick-up shoes 18 by delivering the electric power to commutator 33. Electrical contact between pick-up shoes 18 and commutator 33 is done by employing brush assemblies 19 which consist of brush assembly casings for housing springs 37 causing shafts 38 to press against rotating commutator 33 during operation of the vehicle.
As shown here, magnets 32 of electric motor 7 are horizontally opposed and located toward the sides of vehicle 20. The attraction of the magnets to the metal electrical rails embedded in the track 42 helps to keep the vehicle 20 on the track during high speed cornering. In some embodiments of the prior art, such as U.S. Pat. No. 4,429,488, the magnets may be vertically opposed, i.e. oriented toward the top and bottom of the car. The magnet on the bottom becomes more strongly attracted to the track, while the magnet on the top is less strongly attracted, but the result is a net increase of the attraction of the magnets to the track, helping further to hold the car to the track during cornering.
The fact that brush assemblies 19 are placed forward of motor 7 and completely within chasis 23, and the coincidence of the planes of drive shaft 16 and rear axle 13, requires that vehicle 20 be of a certain minimum size to allow for such placement.
To reduce the size of the vehicle, it has been found that it is not feasible to locate these elements in their prior-art configuration. Specifically, significant reduction in length requires that the drive shaft and wheel axles not remain in coincident planes. Thus, the use of only a drive pinion and spur gear as used by the prior art is not feasible in reducing the size of the vehicle as contemplated herein.
Also, the placement of the brush assemblies are placed forward of the motor and completely within the chasis similarly limits the minimum length of the vehicle.